prolonging battery life as long as possible?

How should i care for my battery? I've been told that its both good and bad to keep it plugged in the whole time and I'm really confused. I just got a new one and I want to baby it as much as possible to keep the battery life as high as possible for as long as I can.
Thanks,
Stephen

one thing that page didn't answer for me: does the ipod (like my ibook) run off charger power if i had it hooked up, in say, a car? because i use it more often there and would invest in the car charger if it wouldn't hurt the battery.

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